PURPOSE: To report the characteristics of infection and prognostic factors of endogenous endophthalmitis (EE) over an 11-year period. METHODS: The clinical records of 41 eyes of 36 patients diagnosed with culture-proven EE at the Rajavithi Hospital were retrospectively reviewed. RESULTS: Median age at presentation was 58 years. Liver abscess (19%) and urinary tract infections (19%) were the most common sources of infection. The most common causative agents were gram-negative organisms (48%). The most commonly isolated microorganism was Klebsiella pneumoniae (26.8%). Worse initial visual acuity and severe intraocular inflammation at first presentation were equally associated with poor visual outcome in the multivariate model (adjusted odds ratio, 20.32; 95% confidence interval [1.12-357.45]; P = 0.040). CONCLUSIONS: Endogenous endophthalmitis usually has a poor visual prognosis. Liver abscess and urinary tract infections are common primary sites of infection. Poor initial visual acuity and severe intraocular inflammation at the initial presentation are predictors of poor visual outcome.